SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 7 days to 28 Jan 2024: Pakistan 171.5 µg/m³, India 70.4 µg/m³ and Montenegro 40.1 µg/m³.
- 1Pakistan4 cities171.5
- 2India5 cities70.4
- 3Montenegro3 cities40.1
- 4North Macedonia7 cities38.9
- 5Serbia12 cities, was 336.8
- 6Thailand84 cities, was 1035.4
- 7Italy24 cities23.4
- 8Hong Kong13 cities23.2
- 9Peru5 cities22.8
- 10Romania8 cities22.0
- 11Chile45 cities19.6
- 12Bulgaria6 cities19.1
- 13Slovakia27 cities16.8
- 14South Africa25 cities16.7
- 15Hungary9 cities16.3
- 16Spain108 cities14.5
- 17Mexico9 cities, was 4614.2
- 18Greece10 cities14.0
- 19Czechia35 cities12.3
- 20Poland76 cities12.0
+ 19 more countries, 11.2 µg/m³ and below
- 36United States744 cities6.1
Not counted on this day, too few cities measured: China since 28 Jan 2024, Iceland since 26 Jan 2024, Reunion since 15 Jan 2024 and 2 more countries.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.